The link between violence and hot weather is so intuitive that it’s embedded in our language: Hotheads lose tempers that flare, anger simmers and comes to a boil, and eventually we cool down.

So what does science have to say? Do tempers truly soar with temperature? The answer, appropriately enough for these triple-digit days, is hazy and hotly contested.

To be sure, extensive literature exists on hot weather and violence, stretching from poorly controlled regional studies in the late 19th and early 20th centuries — oh, those hot-blooded southerners! — to more sophisticated modern analyses. Thi...

A teardown of the new 13-inch MacBook Air reveals the logic board, in its tiny, mighty glory. Photo courtesy of iFixit

A quick peek under the hood of Apple’s new MacBook Air reveals the company’s diligent efforts to squeeze in its brand-new Thunderbolt technology.

Gadget repair site iFixit dissected the new laptop to look at its chip board, which includes an Intel Core i5 processor and an integrated Intel HD 3000 graphics chip. The chip layout opens space for an Intel platform controller hub with Thunderbolt technology.

“Shifting to integrated graphics on the processor freed up a lot of room on t...